How does the State define a non-inventory or non-jurisdictional dam?
(Source - 2011 Hydrologic Safety of Dams Survey (Updated 2014 except as noted))
STATE
ALABAMA
ALASKA
ARIZONA
ARKANSAS
CALIFORNIA
COLORADO
CONNECTICUT
DELAWARE
FLORIDA
GEORGIA
HAWAII
IDAHO
(updated 2016)
ILLINOIS
How does the State define a non-inventory or non-jurisdictional dam?
Minimum criteria:
No State Program
Less than 10 feet in height and poses no threat to lives and property; less than 20 feet in height,
impounding less than 50 acre-feet and poses no threat to lives and property.
(a) any barrier that is or will be less than six feet in height, regardless of storage capacity
(b) any barrier between 6 and 25 feet in height with a storage capacity of less than 50 ac-feet
(c) any barrier that has or will have a storage capacity of fifteen acre-feet or less, regardless of
height
(d) any barrier for the purpose of controlling liquid-borne material
(e) any barrier that is a release-contained barrier (f) any barrier that is owned, controlled, operated,
maintained or managed by the United States Government or its agencies or instrumentalities if a
safety program that is as least as stringent as the state safety program applies and is enforced
against the agent or instrumentality.
Less than 25 feet dam height or less than 50 acre-feet of storage (top of dam)
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
We also have other execptions to jurisdiction.
Less than 100 acre-feet or creates a reservoir with a surface area less than 20 acres at the highwater line, or is less than 10 feet in height.
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
Or all other dams with an impoundment capacity of three (3) acre-feet or less.
any one of the following: privately owned; low hazard; less than 6 feet high; less than 15 acre-feet of
storage
Dam safety in Florida is a shared responsibility among the Florida Department of Environmental
Protection (FDEP), the regional water management districts, the United States Army Corps of
Engineers (USACE), the local government and private dam owners.
http://www.dep.state.fl.us/water/mines/damsafe.htm
Less than 25 feet or stores less than 100 acre-feet. Also those less than 6 feet in height regardless of
storage capacity or which have storage capacity of less than 15 acre-feet regardless of height.
< 25ft height & < 50acft volume at max water surface elevation; or < 6 ft height; or
< 15 acft volume at max water surface elevation
Dams and reservoirs subject to regulation for public safety are 10 feet or more in height and an
impounding capacity of 50 acre-feet or more; any hydraulic structure regardless of size may be
regulated for public safety if the potential failure consequences would result in significant damage to
downstream life or property.
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
Also, if the drainage area of the dam is 6400 acres or less in a rural area, or 640 acres in an urban
area
INDIANA
The drainage area above the dam site is less than one square mile; the height of the dam above the
natural stream bed or the lowest point on the valley floor is less than 20 feet; the volume of water
impounded by the dam to the emergency spillway level is less than 100 acre-feet; or the rights of
other property owners are affected.
IOWA
Iowa Jurisdictional thresholds: a. Any dam designed to provide a sum of permanent and temporary
storage exceeding 50 acre-feet at the top of dam elevation, or 25 acre-feet if the dam does not have
an emergency spillway, and which has a height of 5 feet or more.
b. Any dam designed to provide permanent storage in excess of 18 acre-feet and which has a height
of 5 feet or more.
c. Any dam across a stream draining more than 10 square miles.
d. Any dam located within 1 mile of an incorporated municipality, if the dam has a height of 10 feet
or more, stores 10 acre-feet or more at the top of dam elevation, and is situated such that the
discharge from the dam will flow through the incorporated area.
KANSAS
KENTUCKY
LOUISIANA
MAINE
MARYLAND
MASSACHUSETTS
MICHIGAN
MINNESOTA
MISSISSIPPI
MISSOURI
MONTANA
NEBRASKA
All dams less than 25 feet high or with a height of six feet or greater and a storage volume at the top
of the emergency spillway elevation of less than 50 acre feet and all low hazard potential dams with
a height of less than 30 feet and storage volume at the top of the emergency spillway elevation of
less than 125 acre feet. In addition all low-hazard potential dams that are wastewater storage
structures for a confined feeding facility are exempt.
Less than 25 feet in height and an impounding capacity of less than 50 acre-feet or no downstream
hazard to human life.
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
LA R.S. 38:22
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
All dams in MD are juridictional regardless of size, although some low hazard dams less than 20 ft
high can be approved by local soil conservation district in lieu of a state waterway construction
permit.
All dams are inventoried. The following are non-jurisdictional:1) any barrier which is not in excess of
six feet in height, regardless of storage capacity, or which has a storage capacity at max water
storage elevation not in excess of 15 acre feet, regardless of height. 2) any barrier with low hazard
potential classification in the use of agriculture.
Less than 6 feet in height or has an impounding capacity of 5 surface acres or less.
Less than 6 feet high; or less than 15 acre-feet of storage; or less than 25 feet high and less than 50
acre-feet of storage with no potential for loss of life; or Federal dam
Less than 8 feet in height, or impounds less than 25 acre-feet, or doesn't impound a stream and
doesn't present a downstream threat
Any artificial or man-made barrier which does or may impound water and is less than 35 feet in
height. Also, all agricultural purpose dams.
Less than 50 acre-feet of storage (top of dam)
All dams regardless of size are jurisdictional dams. Only High Hazard dams and 50 acre-feet or larger
are required to be permitted.
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
All dams are "jurisdictional" so non-inventory are: Less than 20 feet in height or less than 20 feet in
height and impounds less than 20 acre-feet of water. Dams permitted under an older standard (10'
NEVADA
high and 10AF of water) are also still inventoried.
NEW HAMPSHIRE Less than 6 feet high.
NEW JERSEY
Less than 5 feet high.
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
NM Law was changed in 2009 to mirror the National Inventory Criteria for the size of a jurisdictional
NEW MEXICO
dam.
A construction permit is required unless the dam is 6 ft high or may impound less than 1 million
NEW YORK
gallons, or is less than 15 ft high AND may impound less than 3 million gallons.
NORTH CAROLINA Less than 25 feet in structural height or less than 50 acre-feet of storage at top of dam elevation
(updated 2016)
unless high hazard. All high hazard dams are jurisdictional.
NORTH DAKOTA
under 12.5 acre-feet of storage
OHIO
OKLAHOMA
OREGON
PENNSYLVANIA
PUERTO RICO
RHODE ISLAND
SOUTH CAROLINA
SOUTH DAKOTA
Dam less than 6 feet in height OR less than 15 acre-feet in storage OR greater than 6 feet and less
than 10 feet in height and less than 50 acre-feet in storage are exempt from Ohio's dam safety laws.
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
15 af or less of impounding capacity irregardless of height of dam and 6 feet to 25 feet in height and
with an impounding capacity of less than 50 acre-feet.
Less than 10 feet in height or that impounds less than 9.2 acre-feet.
Less than or equal to 15 feet and the impounding capacity at maximum storage elevation is less than
or equal to 50 acre-feet and the drainage area is less than or equal to 100 acres..
Is 25 feet or less in height or has an impounding capacity at the maximum water storage elevation of
50 acre-feet or less.
RI defines a 'regulated' dam as a low hazard dam that is six (6) feet or more in height or has fifteen
(15) acre-feet or more of storage capacity; or a high hazard dam; or a significant hazard dam. 'Not
regulated' doesn't meet the criteria. 'Non-jurisdictional' dams are FERC (for example), not RI,
regulated. 'Non-inventory' are dams that we don't have in our database (typically small dams that
wouldn't be regulated.
Less than 25 feet in height or shall have an impounding capacity at maximum water storage
elevation of less than 50 acre-feet.
A barrier is not considered a dam if height does not exceed 6 feet regardless of storage capacity of if
storage capacity does not exceed 15 acre-feet.
TENNESSEE
TEXAS
UTAH
VERMONT
VIRGINIA
WASHINGTON
WEST VIRGINIA
WISCONSIN
WYOMING
Dam means any artificial barrier, together with appurtenant works, which does or may
impound or divert water, and which either (1) is or will be twenty (20) feet or more in height from
the natural bed of the stream or watercourse at the downstream toe of the barrier, as determined
by the Commissioner, or (2) has or will have an impounding capacity at maximum water storage
elevation of thirty (30) acre-feet or more. Provided, however, that any such barrier which is or will
be less than six (6) feet in height, regardless of storage capacity, or which has or will have a
maximum storage capacity not in excess of fifteen (15) acre-feet, regardless of height, shall not be
considered a dam, nor shall any barrier, regardless of size, be considered a dam, if, in the judgment
of the Commissioner, such barrier creates an impoundment used only as a farm pond.
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
Texas law exempts privately-owned significant hazard potential dams storing less than a maximum
of 500 acre-feet in counties with population less than 350,000, excluding dams within municipal
corporate limits.
Owned by Bureau of Reclamation
Non jurisdictional: Capable of impounding 500,000 cubic feet or less of water. No non-inventory
dam in VT, all dams we know of are included in inventory.
Owned or regulated by the Federal Government, or Permitted Mining Dam, or size exempt. Size
exempt: <6', or <50 ac-ft for dams 6' - 25', or <15 ac-ft for dams >25'. Dams operated primarily for
agricultural purposes which are less than 25 feet in height or which create a maximum
impoundment capacity smaller than 100 acre-feet.
Non-jurisdictional - Less than 10 acre-feet of storage (top of dam); USACE or USBR ownership; or
FERC regulation. Of the unregulated dams, 106 are high hazard USACE, USBR or FERC dams.
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
Exemptions for federal owned dam, farm pond dams, and road fills that do not normally impound
water
Less than 25 feet high (from streambed) and 15 acre-feet of storage (top of dam)
Less than 6 feet high (from streambed) and 50 acre-feet of storage (top of dam)
The state definition of Large Dam matches the NID criteria. Also, dams associated with cranberry
production and dams not located on a watercourse.
Anything less than 15 acre-feet regardless of height, less than or equal to 6 feet in height regarless
of capacity, or less than 20 feet in height and less than 50 acre-feet.